2012 eruption of Mount Meridian
The 2012 eruption of Mount Meridian, a stratovolcano located close to Leeds, is a major ongoing volcanic eruption. The eruption (which is currently rated as a VEI 5 event) is the first one on Animal Crossing Island for 70,000 years. The eruption was very similar to the 1980 eruption of Mount St. Helens in the USA, but ended up being more powerful and was of similar power to the 1991 eruption of Mount Pinatubo in the Philippines. Buildup to the eruption The eruption was preceded by several months of activity that included earthquakes and steam coming out of the volcano's crater. Although the steam being sighted coming from the crater is normal, due to the local hot springs, it had never before been witnessed so often as prior to the eruption. As well as this, there was a growing bulging dome (a cryptodome, not a lava dome as many thought) along the south (Leeds-facing) face of the mountain. However, scientists were almost certain that the volcano was extinct and would never erupt again, and they called these steam ventings and earthquakes and domes a minor blip in the history of the dead volcano. In the end, however, these 'warnings' culminated in the beginning of the eruption on 15 March 2012. 6.5 earthquake and landslide Late during the night of 15 March 2012, measured by seisometers as 23:56:17, an earthquake of magnitude 6.5 shook the whole mountain. Around ten seconds after the end of the earthquake, the bulge on the south face of the mountain collapsed in an almighty landslide, and the whole south face of the mountain slid away. This is thought to have been the largest landslide in terms of volume in living memory. It travelled south for 2 miles, before a ridge slowed it down and deflected it westwards, away from Leeds, and it eventually went on to travel a further 23 miles east. One valley was completely filled with landslide material to the point that it was no longer a valley, just flat land. The eruption 15 March When the south face slid away, it revealed the magma chamber. The rapid decompression of the magma chamber as outside air flooded in caused a very sudden, explosive eruption to begin approximately 25 seconds after the end of the earthquake, throwing out hot rock, lava, pumice, ash, and water (from blown-apart melting glaciers) initially upwards and through the hole to the south. The initial explosive eruption measured VEI 5. Eventually these gathered up into a lahar and pyroclastic flow and travelled behind the landslide, hitting areas around 5 minutes after they were hit by the landslide causing a second devastation. The more fluid lahar/pyroclastic flow eventually overtook the landslide, and travelled 39 miles from the volcano's crater before flowing, dramatically, into the sea on an abandoned stretch of coastline, with lots of steam. The initial shockwave from the explosive eruption was marked and felt as "a second earthquake", measuring 4.5 on the Richter scale and blowing out windows as far away as San Costa. 16 March Ten minutes after the eruption began, the ash cloud had already reached 10,000 feet, moving at 1,000 feet per minute but starting to slow down. The eruption "calmed down" and became less explosive by around 0200 on 16 March. By this point, material had stopped coming out of the gap in the south face and was all now being blown upwards out of the crater into the sky. As a result volcanic bombs rained down on areas as far away as San Costa, where two people were killed after being struck down by a van-sized piece of pumice in the middle of their road, which measured 1000 degrees Celsius. The ash cloud reached it's maximum 80,000 feet my midday, where it stopped rising and started fanning out like a mushroom cloud. From midday the eruption appeared to be slowing down and by sunset the ash cloud was much smaller and eruptions only at VEI 1-2 scale. 17 March A second explosive eruption phase started at 0800 on 17 March. Although it was more powerful, measuring VEI 6, less large rocky material (pumice etc.) was ejected. This is thought to have been because it was either mostly removed in the initial explosive eruption, or it might have been blown straight up and then straight back down into the crater. However, 10 times more ash was released by the second eruption. The ash cloud reached over parts of northern and western Europe by 0900 and it even grazed the northern coast of Morocco in northern Africa. Fourteen European countries - Leeds, Spain, Germany, France, Ireland, United Kingdom, Denmark, Sweden, Finland, Poland, Estonia, Lithuania, Latvia, and European Russia - closed their airspace. In north Africa, Morocco and Tunisia also closed theirs, bringing the total to 16 countries. By 0900 ash had started falling in Leeds, coating surfaces with a thin coating of brown dust and causing a brown haze. Residents were warned about possible health effects from inhaling ash and free respirators were given to every resident to wear when going outside. They said that no only would this protect from the ash, but it could also protect partially from the 2011-2012 Leeds norovirus pandemic.